A study is to be made of the controlled potential electrolysis of Vitamin B12 compunds on Pt, Au, and graphite electrodes with the goal of preparing Vitamin B12r and B12s in the absence of excess reducing agent and catalytic impurities from the electrode. Also attempts will be made to develop electroanalytical methods such as pulse polarography and cyclic voltammetry for analysis of various forms of the vitamin at solid electrodes. These techniques and others such as visible spectrophotometry and esr measurements will be used to study the reaction kinetics of B12r with alkylating agents. The B12r will be electrogenerated at the solid electrodes and the reaction kinetics followed in the absence and then in the presence of ligands such as thiols and sulphides. It is hoped that a mechanism can be worked out for the alkylation of vitamin B12a in the presence of thiois and an alkylating agent. Finally the rate of heterogeneous electron transfer will be studied for various B12 redox couples on various electrodes.